Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/013—Preparation of halogenated hydrocarbons by addition of halogens
  • C07C17/02—Preparation of halogenated hydrocarbons by addition of halogens to unsaturated hydrocarbons

Definitions

• the crude, catalyst-containing dichloroethane formed is generally drawn off from the reaction vessel and treated with water or aqueous alkali solutions to remove the catalyst and the hydrogen chloride contained in the crude product and then worked up by distillation using known processes.
• FeC1 3 as a catalyst in the addition chlorination of ethylene is associated with certain disadvantages.
• FeC1 3 has a corrosive effect on the metallic materials of reactors, columns or heat exchangers insofar as they come into contact with the catalyst.
• the chlorine of technical purity normally used for chlorination always contains traces of moisture;
• hydrogen chloride always arises from undesirable side reactions.
• the reaction must be carried out at temperatures above the boiling point of dichloroethane at atmospheric pressure. Since the rate of corrosion increases significantly with increasing temperature, it is essential to equip the chlorination reaction equipment with corrosion-resistant materials, which impairs the economics of the process used.
• the invention thus relates to a process for the preparation of 1,2-dichloroethane by reaction of ethylene with chlorine in a solvent in the presence of a catalyst and, if appropriate, an inhibitor for preventing the formation of by-products at a temperature of about 20 to 200 ° C. and normal or Overpressure and separation of the 1,2-dichloroethane from the chlorination mixture by distillation, which is characterized in that an anhydrous tetrachloroferrate (1-) is used as the catalyst or those substances are used which are capable of forming a tetrachloroierate (1-) in the reaction mixture.
• a tetrachloroferrate (1-) whose cation is an alkali metal or alkaline earth metal or an ammonium ion is preferably used as the catalyst.
• the catalyst in a concentration of about 0.005 to 0.5% by weight, calculated as ferric chloride and based on the amount of solvent.
• a preferred embodiment of the process of the invention is to use dichloroethane as a solvent and oxygen or air as an inhibitor.
• the catalysts can be prepared in a known manner.
• Anhydrous ammonium tetrachloroferrate (1-) can be obtained by melting a mixture of stoichiometric amounts of ammonium chloride and anhydrous ferric chloride.
• the catalyst according to the invention is generally dissolved or suspended in the solvent placed in the reactor. However, it can also be prepared outside the reaction solution and introduced into the reactor. It is also possible to feed the solvent initially introduced into the reactor with anhydrous FeC1 3 and a water-free further component which is soluble in the reaction medium and is capable of forming the tetrachloroferrate. Finally, the tetrachloro ferrate (1-) are formed in the reaction mixture in such a way that the reaction mixture is ate, for example, with (NH 4 ) 2 FeCl 5 . H20 or a tetrachloroferrate (2-) and the latter anion in the reaction medium is oxidized to a tetrachloroferrate (1-).
• the catalysts according to the invention can be described as technically progressive, since they significantly reduce the corrosion which occurs and is disadvantageous in known processes for the preparation of 1,2-dichloroethane when using non-corrosion-resistant, metallic reactors. It was also found that, with the exception of small amounts of the first substitution product 1,1,2-trichloroethane and a correspondingly small amount of hydrogen chloride, virtually no further by-products are formed under the process conditions according to the invention. The reaction solution remains bright even with a longer reaction time if ammonium tetrachloroferrate (1-) is present in the reaction solution. A reaction mixture which is possibly already dark in the course of the reaction lightens again to the extent that the compounds mentioned are added as the reaction proceeds. Finally, it should be noted that in the process of the invention the conversion is almost quantitative with a high space / time yield.
• the process of the invention can be carried out, for example, in the loop reactor described in DE-OS 24 27 045 or in any other reactor which is suitable for carrying out the process.
• a loop reactor made of glass having a capacity of about 2 1 2.0 kg of 1,2-dichloroethane containing 0, 1 - 0.3 wt% of a catalyst containing dissolved listed in the table presented.
• the rising part of the reactor loop contained a packed layer. Below the packing layer were inlet pipes into the reactor for ethylene, chlorine and air, through which approximately 60 1 / h of chlorine and ethylene and 15 1 / h of air were fed.
• the reactor liquid was circulated in the reactor system according to the mammoth pump principle. During the reaction, a temperature of approximately 77 ° C. was established in the reaction mixture.
• the dichloroethane vapors withdrawn from the reactor were condensed in a water cooler arranged above the reactor and then a portion of the condensate corresponding to the amount produced was branched off and removed by means of a condensate divider, while excess condensate was returned to the reaction zone.
• Another dichloroethane component was separated from the exhaust gas, which mainly consists of inert gases, by means of a cold trap.
• the crude dichloroethane obtained had the composition shown in the table.
• the yield of crude dichloroethane was on average 267 g per hour, whereby it must be taken into account that the gas quantities entered were only determined by means of flow measuring devices. Despite a steel body inserted into the reactor, the iron content in the reaction mixture remained unchanged.
• a mixture of 4341 g of 1,2-dichloroethane and 3.3 g of FeCl 3 was placed in a stirred vessel with a volume of 5 l.
• the FeCl 3 content determined by colorimetry was 0.076% by weight.
• 1.1 g of Na 2 CO 3 were added to the magnetically stirred solution.
• 60 l of chlorine gas and 15 l of air per hour were introduced into the mixture introduced via an inlet tube and 60 l / h of ethylene were introduced via another tube with glass frit.
• the dichloroethane vapors withdrawing from the reactor were condensed in a water cooler arranged above the reactor and then a portion of the condensate corresponding to the amount of dichloroethane produced was branched off and removed by means of a condensate divider, while excess condensate was returned to the reaction zone.
• a further trap of condensate was separated from the exhaust gas, which mainly consists of inert gases, using a cold trap.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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• 1982
  • 1982-12-08 DE DE19823245366 patent/DE3245366A1/de not_active Withdrawn
• 1983
  • 1983-11-08 CA CA000440682A patent/CA1225103A/fr not_active Expired
  • 1983-11-10 IN IN1378/CAL/83A patent/IN159104B/en unknown
  • 1983-11-11 ES ES527213A patent/ES8406407A1/es not_active Expired
  • 1983-11-22 DE DE8383111651T patent/DE3369122D1/de not_active Expired
  • 1983-11-22 EP EP83111651A patent/EP0111203B2/fr not_active Expired - Lifetime
  • 1983-11-23 US US06/554,586 patent/US4774373A/en not_active Expired - Lifetime
  • 1983-11-29 JP JP58223422A patent/JPS59116237A/ja active Granted
  • 1983-12-06 SU SU833673517A patent/SU1277887A3/ru active
  • 1983-12-06 CS CS839129A patent/CS240984B2/cs unknown
  • 1983-12-06 DD DD83257559A patent/DD215528A5/de not_active IP Right Cessation
  • 1983-12-06 BR BR8306694A patent/BR8306694A/pt not_active IP Right Cessation
  • 1983-12-07 HU HU834187A patent/HU191906B/hu not_active IP Right Cessation
  • 1983-12-07 MX MX199651A patent/MX160807A/es unknown
  • 1983-12-07 ZA ZA839089A patent/ZA839089B/xx unknown
  • 1983-12-07 NO NO834509A patent/NO156863C/no not_active IP Right Cessation
  • 1983-12-07 AU AU22161/83A patent/AU558826B2/en not_active Ceased

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